Vibratory finishing apparatus



Sept. 5, 1967 J. F. RAMPE 3,339,316

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l `VIBRATORY FINISHING' APPARATUS Filed April V, 1965 6 Sheets-Sheet 3 Sept. 5, 1967 1. F. RAMPE VIBRTORY FINISHING APPARATUS 6 Sheets-Sheet Filed April 7, 1965 Sept. 5, 1967 J. F. 'RAMPE 3,339,316

VIBRATORY FINISHING APPARATUS Filed April '7, 1965 6 Sheets-Sheet 5 l NVENTOR.

Sept. 5, 1967 J. F. RAMPE VIBRATORY FINI'SHLNG APPARATUS 6 Sheets-Sheet 6' Filed April 19651 United States Patent 3,339,316 VIBRATORY FINISHING APPARATUS John F. Rampe, 3417 Fairfax Road, Cleveland Heights, Ohio 44118 Filed Apr. 7, 1965, Ser. No. 446,376 Claims. (Cl. 51-163) This invention relates to finishing apparatus and more particularly to vibratory finishing apparatus of the orbital type.

In my co-pending United States applications, Ser. No. 261,981 filed Mar. 1, 1963, now Patent No. 3,191,348 issued June 29, 1965 and Ser. No. 409,166 filed Nov. 5, 1964, now Patent No. 3,300,908 issued Ian. 31, 1967, there are disclosed and described orbital type vibratory finishing apparatus for the surface finishing of metal articles such as castings, forgings, stampings, etc. as well as for the surface finishing of plastic articles and articles formed of similar materials. In these apparatus, a work holding tub is mounted on a carriage which is in turn supported on a fixed frame by resilient shear type mounts whereby the carriage and the tub may have orbital movement relative to the frame. A counterpoise structure is also supported on the fixed frame of each of these devices adjacent to the tub carriage by resilient shear type mounts and a common eccentric drive shaft means s adapted to impart orbital movement to both the tub c arriage and the counterpoise structure whereby the forces imposed on the eccentric drive shaft by the orbital movement of the resiliently mounted tub carriage and tub are opposed and dynamically balanced by the forces imposed on the eccentric driveshaft by the orbital movement of the resiliently mounted counterpoise structure. This arrangement provides a smooth running mechanism which may be operated at high speed without setting up dangerous and harmful vibrations in the apparatus itself or in the building in which it is housed.

In the apparatus of the present invention, counterbalanced support and drive means are employed for a Work carrying tub which are similar in some respects to those of my co-pending applications.

In the operation of the finishing apparatus of these types, an abrasive medium or other suitable material selected according to the results desired is charged into the tub with the articles to be finished. Preferably, surface processing of parts is accomplished with the abrasive media suspended in water, or other suitable fluids. Preferably, enough fluid is employed for easy flow and circulation. Typical media are bonded aluminum oxide and silicon carbide. The media size is determined by the desired abrading or finishing rate. In general, small sizes of media grind more slowly but produce a finer finish. Larger sizes of media grind faster but leave a coarser surface. Random-shaped chips are generally used on parts which have liberal tolerances and do not have lodgement problems. In the case of compound finishing, one-third or one-half of the compound used for tumble barrel finishing generally is sufficient for orbital finishing.

The amount of liquid introduced into the tub has a bearing on the rate at which cutting action takes place. For example, low water levels accelerate the cutting action and high water levels with slippery and lsoapy compounds create a damping effect and reduce cutting action with improved polishing and burnishing. A relatively large amount of water is preferable when processing delicate parts such as watch hands to slow their movement through the mass. Although the predominant use of this apparatus'is in finishing metal parts, it is equally suitable to finishing non-metallic parts, such as plastic, and may advantageously be employed to remove rim flash from plastic pieces.

Maximum efliciency of the apparatus is obtained by filling thetub with workpieces without overflowing during operation. With this relationship, proper circulatory motion occurs and most important, the mass weight of maximum depth gives the greater pressure of abrasives against the work. Therefore, the cutting action increases as the mass vibrates within the tub, producing a uniform scrubbing motion through the media and within hard to reach corners and openings.

The time of each work operation varies greatly and depends upon the size of the burr accessibility of the media, the correct operating conditions and the proper compound. Typical cycles of operation are as follows: deburring, 60 minutes; burnishing, 30 minutes; descaling, 10 minutes; cleaning, less than 10 minutes. The higher the frequency of orbital motion, the greater the inertial force against the work parts to increase the cutting action. Similarly, a greater amplitude of orbital path will increase the cutting action.

In the apparatus of this invention, I have provided a construction which is simple to manufacture and assemble, which is relatively compact and is quite economical. Further, this structure develops dynamic forces in the counterpoise which are closely related to the dynamic forces developed by the work carrying tub and its associated carriage such that the vibrations translated to the frame are reduced in comparison -to prior devices.

Other objects and advantages relate to certain novel features and structure and combinations and arrangements of parts which provide economy in manufacture and operation. The invention is described in connection with the accompanying drawings forming a part of the specification and illustrating a preferred embodiment which represents the best known mode of practicing the invention.

In the drawings:

FIG. 1 is a perspective view of one illustrative embodiment of this invention;

FIG. 2 is a View in perspective, partly in section and partly broken away, of the embodiment of FIG. 1, to an enlarged scale with the cover removed;

FIG. 3 is a front view of the apparatus of FIG. 1 to an enlarged scale with the cover and tub removed;

FIG. 4 is a side elevational View taken along the lines 4 4 of FIG. 3;

FIG. 5 is a plan view taken along the lines 5-5 of FIG. 3;

FIG. 6 is a view in perspective of the vibratory system of the apparatus to the same scale as FIG. 2;

FIG. 7 is a side view in elevation to the same scale as FIG. 3 of the counterpoise; and

FIG. 8 is a plan view of the counterpoise of FIG. 7.

. Referring now to the drawings, one embodiment of a finishing apparatus A is shown which is mounted on a base B including a pair of rails 11, 12 each having supporting feet in the form of fiat plates 14, 15 on opposite ends thereof. The apparatus A includes a -tub 16 mounted centrally and at the top thereof. The framework and portions of the tub lare enclosed in a suitable cover 17 of which the front 18 and a side 19 are shown in FIG. 1. To vary the speed of orbital movement in substantially the same manner as described in the above mentioned applications a hand wheel 20 is mounted on a shaft 21 projecting through the side 17 of the cover from the drive mechanism.

The apparatus includes a frame F having four legs 23, 24, 25 and 26, each secured to one end of one of the base defining rails 11 and 12. The legs 23, 24 are provided with upper and lower cross braces 28, 29, respectively. Frame legs 25, 26 are provided with cross braces 30, 31 on the upper and lower extremities, respectively. Lifting tongues 33, 34 are mounted on the horizontal leg braces 28, 30, respectively, for the purpose of hoisting and positioning the nishing apparatus A relative to the oor of the factory, see FIGURE 20.

The frame F supports a vibratory system including a carriage C on which the tub 16 is mounted and a counterpoise assembly D. The counterpoise assembly includes a pair of H-shaped counterpoise members 35, 36 mounted on the outside of the frame F. The carriage C is mounted on the inside of the frame F between the frame legs 23, 24, 25 and 26. The tub 16 is provided with a discharge spout 27 within which is positioned a suitable discharge door (not shown) in the tub wall.

The carriage C includes four vertically extending legs 36, 37, 38 and 39 each positioned within one of the frame legs 23, 24, 25 and 26. The carriage legs are supported from the frame legs by means of resilient shear type bushings. For example, the leg 36 is supported by bushings 40, 41 the opposite ends of each of which includes a bolt which threadably engages a plate, not shown, recessed in the end of a resilient rubber body. Each carriage leg is reinforced by a longitudinal anglemember 42 which is L shaped in cross-section and is mounted on the inside of the leg with the angle facing the tub 16. Similarly, the leg 37 is mounted on the leg 25 by means of resilient mounts 43, 44. Similarly, the leg 38 is mounted on the frame leg 24 by means of a pair of resilent mounts 45, 46. The leg 39 is mounted on the frame leg 26 by means of a pair of shear mounts 47, 48. The carriage legs 36, 37 are connected together by a carriage side member 50, which supports -a suitable bearing block assembly 52. The legs 38, 39 are connected together by a side member 54 which supports a bearing block assembly 55.

A main drive shaft 53 is rotatably mounted in the bearing block assemblies 52, 55. The drive shaft 53 is a cylindrical member having two eccentric sections or two pairs of diammctrically opposed eccentric sections. The first pair of eccentric sections is designated 57, 58 and 'these eccentric sections engage the bearing assemblies 52, 55, respectively. The second pair of eccentric sections is designated 60, 61 and these sections are rotatably journalled in the bearing assemblies 62, 63 on the counterpoise assembly D and specifically on the cross arm members of the counterpoise assembly.

The drive shaft 53 supports a variable speed pulley 65 which is coupled to a prime mover such as an electric motor 67 by means of a pulley 68 on the drive shaft 69 of the motor 67 and a flexible belt 70. Because of the diammctrically opposed relationship of the pairs of eccentrics relative to the drive shaft S3, the counterpoise D and the carriage C will be driven through opposed orbits. The carriage assembly includes a pair of longitudinal tub rails 74, 75 which are angularly shaped members welded or otherwise fastened to the carriage cross arms 50, 54. The tub 16 is generally cylindrical in cross-section and is provided with a suitable base 77 which is U-shaped in cross-section and is welded, or otherwise secured, to the tub securely to hold the tub in position between the rails 74, 75.

Id this particular illustrative embodiment, the tub has its axis substantially parallel to the axis of drive shaft 53 and is designed to carry a load of the order of 30D-400 pounds. This load includes the workpieces to be finished and the abrasive material and liquid which is to perform the finishing operation. Also, the tub is aligned on the carriage such that the centerline of the tub lies in the same vertical plane as the centerline of the drive shaft 53. A pair of weight assemblies is mounted on the opposite ends of the carriage legs 36, 37, 38 and 39 from the tub 16 to act as dynamic balances for the tub assembly `and design load. As shown in FIGS. 3 and 5, the weight assemblies include a pair of channel members 79, 80 each of which is Connected between a pair of legs of the carriage and each of which supports a bar weight 81, 82, respectively.

In the dynamic balancing of the carriage assembly and tub including the design load, relative to the axis of the drive shaft 53, utilization is made of relatively long torque arms for the Weight assemblies relative to the torque arm of the center of gravity of the tub and design load. For example, in this specific embodiment, the center of gravity of the tub and design load is displaced, relative to the drive axis, a distance of the order of twelve inches. Each of the weight assemblies on the lower ends of the carriage legs is displaced from the centerline of the shaft axis at least one-and-a-half times the tub displacement or at least eighteen inches. Thus, the weight assemblies act as dynamic balances for the tub including the design load by means of weight assemblies which have a combined weight substantially less than that of the tub and design load.

In this specific embodiment, the tub with design load weighs within the range of 450-550 pounds and the counterweight assemblies weigh a total of the order of 125 pounds. It is, of course, understood that a longer torque arm or effective torque arm on the counterweights 81, 82 and the supporting channel members 79, 80 would provide a greater torque. A torque arm in the range of one-and-a-half to two times the torque arm of the tub and design load is preferred.

The counterpoise assembly D includes a pair of identical H shaped counterpoise members 35, 36 on the opposite sides of the frame F for dynamically balancing the carriage assembly C; accordingly, only the details of member 35 will be described.

The counterpoise member 35, which is the front member, includes a main bar 85 on which is centrally mounted the previously mentioned thrust bearing assembly 63. Two pairs of gussets 86, 87 and 88, 89 are secured to opposite ends of the main bar 85 to increase the weight of the counterpoise and to provide relatively long torque arms as measure-d from drive shaft 53. These gussets are secured, as by welding, to the main bar 85. The mass of the counterpoise 35 is further increased by the addition of rectangular blocks 90, 91 on sides of the main bar 85 and at equal `distances from the drive shaft 53 and with their centers of gravity in the same horizontal plane as drive shaft S3. The counterpoise 35 includes a pair of vertically extending support arms 92, 93 which receive bolts, such as 94, 95, 96 and 97, engaging the resilient shear type mounts 98, 99, 100 and 101.

It is to be noted that the support arms 92, 93 extend equal distances from the horizontal centerline of the main bar 85 such that the torques on the respective bolts 94, 95, 96 and 97 will be substantially balanced. Further, because of the additional masses attached to the main bar 85, the center of gravity of each half of the counterpoise assembly 35 relative to the drive shaft axis will lie within the outer edge of the support arms 92, 93 and preferably adjacent the inner edge of the support arms 92, 93. Still further, because of the symmetry of the counterpoise assembly relative to the horizontal line through the axis of the drive shaft, the center of gravity of the counterpoise assembly lies on the horizontal line which contains the drive shaft axis.

In accordance with the patent statutes, the embodiments shown in the drawings are merely for purposes of explanation and illustration without intending to limit the scope of the claims to the specific details disclosed: it is intended that the patent shall cover, by summarization in appended claims, all features of patentable novelty residing in the invention.

What is claimed is:

1. In an orbital finishing apparatus, the combination comprising:

a frame including a base and a group of vertically extending members connected to said base;

a carriage resiliently mounted on said frame by means of a plurality of resilient shear mounts' and having a pair of opposed bearing block assemblies;

a generally cylindrical workpiece supporting tub mounted on said carriage;

an eccentric drive shaft rotatably mounted in said bearing block assemblies; and

a counterpoise assembly including a pair of H-shaped members each having a pair of legs connected by a crossbar and a bearing block assembly in each crossbar rotatably supporting said drive shaft, each of said H-shaped members having its center of gravity in a horizontal plane containing said drive shaft.

2. The combination according to claim 1 wherein each counterpoise leg extends substantially equal distances on each side of the horizontal plane through the axis of said drive shaft.

3 The combination according to claim 1 including torque balancing means mounted on said carriage on the opposite side of said drive shaft from said tub.

4. In an orbital finishing apparatus, the combination comprising:

a frame;

a carriage having a generally cylindrical workpiece supporting tub thereon and a pair of aligned bearing assemblies;

a first plurality of shear mounts resiliently supporting said carriage on said frame;

a counterpoise assembly including a pair of H-shaped members each including crossbar means, a pair of legs connected to said crossbar means, and a bearing assembly, the center of gravity of each of said H- shaped members lying in a horizontal plane bisecting the bearing assembly;

a second plurality of shea-r mounts resiliently supporting said counterpoise assembly on said frame; and

eccentric drive shaft means rotatably journalled in said bearing assemblies.

5. The apparatus according to claim 4 wherein said carriage includes a plurality of vertically extending members, said tub being mounted on said carriage above said eccentric drive shaft means and wherein said carri-age inclu-des torque balancing means mounted below said eccentric drive shaft means a distance greater than the distance from said eccentric drive shaft means to the center of gravity of said tub when said tub contains its design load.

6. In an orbital finishing apparatus, the combination comprising:

a frame including a base and four vertically extending uprights, each positioned at one corner of a rectangle and mounted on said base;

a carriage including four vertically extending legs and means connecting said legs in pairs, said means supporting a pair of opposed bearing assemblies;

a plurality of shear mounts resiliently supporting said carriage between said uprights;

a generally cylindrical workpiece supporting tub on said carriage with the tub axis in a generally horizontal plane;

a counterpoise assembly including a pair of H-shaped members each including a pair of legs and a horizontal bar connecting Said legs and supporting va bearing assembly;

-a second plurality of shear mounts resiliently supporting said pair of H-shaped members on the outside of said frame;

eccentric drive shaft means rotatably journalled in said bearing assemblies; and

a pair of weight assemblies mounted on the lower portions of said carriage legs with the longitudin-al axes of said weight assemblies substantially parallel to said tub axis.

7. An apparatus according to claim 6 wherein each of s-aid H-shaped members has a pair of weights on each end of said horizontal bar.

8. An apparatus according to claim -6 wherein each of said H-shaped members has a pair of weights thereon, one of said weights being mounted on either side of said bearing assembly on said horizontal member and between said bearing assembly and said counterpoise legs.

9. An apparatus according to claim 6 wherein said counterpoise legs have their transverse centerline positioned substantially within the horizontal plane bisecting the connecting horizontal b-ar. t

10. The combination according to claim 6 wherein the distance from the axis of the drive shaft to the tub axis is less than one third the distance from said drive shaft axis to the centerline of said weight assemblies.

References Cited UNITED STATES PATENTS 2,693,320 11/1954 Smith 241-175 2,756,973 7/ 1956 Dostatni 259-72 2,973,606 3/1961 Brandt 51-163 HAROLD D. WHITEHEAD, Primary Examiner. 

1. IN AN ORBITAL FINISHING APPARATUS, THE COMBINATION COMPRISING : A FRAME INCLUDING A BASE AND A GROUP OF VERTICALLY EXTENDING MEMBERS CONNECTED TO SAID BASE; A CARRIAGE RESILIENTLY MOUNTED ON SAID FRAME BY MEANS OF A PLURALITY OF RESILIENT SHEAR MOUNTS AND HAVING A PAIR OF OPPOSED BEARING BLOCK ASSEMBLIES; A GENERALLY CYLINDRICAL WORKPIECE SUPPORTING TUB MOUNTED ON SAID CARRIAGE; AN ECCENTRIC-DRIVE SHAFT ROTATABLY MOUNTED IN SAID BEARING BLOCK ASSEMBLIES; AND 